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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32501 results found.

  1. GRB 240415B: GECAM-B detection
  2. EP 240416a: Xinglong and NOT decaying optical counterpart
  3. GRB 240415A: Swift-BAT refined analysis
  4. EP240416A: MASTER optical observations
  5. GRB 240411A: Glowbug gamma-ray detection
  6. GRB 240414A: Swift-BAT refined analysis
  7. EP240416a: Kinder optical counterpart candidate
  8. GRB 240414A: AbAO optical upprer limit
  9. GRB 240415A: Swift/UVOT Detection
  10. EP240413a: BOOTES-2/TELMA Optical Upper Limit
  11. GRB 240415A: Fermi GBM Observation
  12. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  13. GRB 240415A: Earliest optical followup with the Kinder observations
  14. GRB 240414A: GMG observation
  15. EP240414a: EP-FXT follow-up observation
  16. GRB 240415B: Swift ToO observations
  17. GRB 240415A: OHP/T193 optical observations
  18. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  19. GRB 240415A: SAO RAS optical observations
  20. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  21. GRB 240414A: Fermi GBM Observation
  22. Fermi GRB 240415A: Global MASTER-Net observations report
  23. GRB 240415A: Mondy optical transient detection
  24. GRB 240414A: Photometric observation from 2.2m CAHA
  25. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 240414A: Swift/UVOT Detection
  27. LXT 240402A/GRB 240402B: Swift follow-up observations
  28. GRB 240414A: Mondy optical observations
  29. GRB 240414A: AKO Optical Upper Limit
  30. X-ray transient EP 240414a - GTC spectroscopic observations
  31. GRB 240415A: Prompt Swift-XRT observations
  32. GRB 240415A: Swift detection of a burst
  33. EP240413a: Upper limits from GECAM-B Observation
  34. EP 240414a: NOT optical counterpart confirmation
  35. GRB240414A : J-band upper limits from WINTER
  36. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  37. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  38. LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
  39. EP240413A: GOTO optical upper limits
  40. GRB 240414A: Skynet Optical Afterglow Observations
  41. Swift GRB 240414A: Global MASTER-Net observations report
  42. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  43. IPN triangulation of GRB 240410A
  44. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  45. IPN triangulation of GRB 240411A
  46. Fermi-LAT gamma-ray observations of IceCube-240412A
  47. GRB 240414A : MITSuME Akeno optical upper limits
  48. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  49. GRB 240414A : OHP/T193 redshift determination
  50. GRB 240414A : OHP/T193 optical counterpart detection
  51. LIGO/Virgo/KAGRA S240413p: Updated Sky localization
  52. LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
  53. EP240408a: GSP optical upper limit
  54. GRB 240411B: CrAO/ZTSh optical observations
  55. GRB 240411B: Kinder observations with Lulin observatory
  56. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  57. LIGO/Virgo/KAGRA S240413p: Identification of a GW compact binary merger candidate
  58. GRB 240411B: HiPERCAM/GTC observation
  59. GRB 240411B: Swift-BAT refined analysis
  60. GRB 240411B: 1.3m DFOT Optical observations
  61. GRB 240411A: GRBAlpha detection
  62. GRB 240411B: OHP/T193 optical observations
  63. GRB 240405A: Glowbug gamma-ray detection
  64. GRB 240411B: LCO optical afterglow detection
  65. GRB 240408B: GRBAlpha detection
  66. EP240408A: MASTER optical observations
  67. EP240408a: GROND detection of a candidate counterpart
  68. EP240408a: Swift follow-up observation
  69. X-ray transient EP240315a: second epoch e-MERLIN radio observations
  70. GRB 240405A: GRBAlpha detection
  71. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  72. Fermi GRB 240408A: Global MASTER-Net observations report
  73. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  74. Fermi GRB 240407A: Global MASTER-Net observations report
  75. Fermi-LAT gamma-ray observations of IceCube-240327B
  76. Fermi-LAT gamma-ray observations of IceCube-240327A
  77. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  78. Fermi GRB 240405B: Global MASTER-Net observations report
  79. GRB 240402C: Glowbug gamma-ray detection
  80. GRB 240331A: GRBAlpha detection
  81. LXT 240402A/GRB 240402B: GECAM-C refined analysis
  82. Swift satellite resumes pointed science observations
  83. GRB 240403A: Glowbug gamma-ray detection
  84. LXT 240402A/GRB 240402B: Glowbug gamma-ray detection
  85. X-ray transient LXT 240402A: WFST optical upper limits​
  86. Konus-Wind detection of LXT 240402A/GRB 240402B
  87. GRB/FXT 240402B: Kinder optical counterpart candidate
  88. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  89. GRB/FXT 240402B: VLT/FORS2 optical afterglow candidate
  90. X-ray transient LXT240402A: AST3-3 optical upper limits
  91. LXT 240402A: EP-FXT detection of the X-ray afterglow
  92. Fermi GRB 240404A: Global MASTER-Net observations report
  93. LXT 240402A: MASTER optical observations with AGN in error-box
  94. GRB 240402B: GWAC-F50A optical upper limit
  95. GRB 240402B: GECAM-C detection
  96. Fermi GRB 240402A: Global MASTER-Net observations report
  97. X-ray transient EP240331a: Kinder optical upper limits
  98. X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
  99. EP240331A: MASTER optical observations
  100. Transient EP240315a: J-band observations of AT2024eju with WIRC

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